of Warming and Ventilating. 54.! 



separate notice. In examining some pine plants grown in pits of the ordi- 

 nary construction, I was delighted to find them also growing after the ordi- 

 nary manner. This speaks forcibly for the system, and demonstrates that 

 any extraordinary effect may be attributed to Mr. Penn's system, rather than 

 to the management, which, however, appeared excellent in every department 

 doing great credit to Mr. Penn's intelligent and most obliging gardener. 



There is, I find, an opinion that this system can only be useful in houses 

 where fire heat is constantly used, and that for green-houses, or mere con- 

 servative structures, it will be nearly useless. My opinion is the reverse of 

 this. In addition to its use in forcing-houses, where it may be deemed 

 indispensable, I would adopt it in the green-house in preference to all other 

 modes of heating. Green-house plants invariably do well while we can admit 

 plenty of air ; or while we can maintain a current to counteract the effects of 

 damp. But there are sometimes months together that we cannot open a sash 

 to effect this, without admitting air injuriously cold, or saturated with moist- 

 ure ; it is then we are doomed to see many of our tender favourites pine, 

 droop, and die ; and then that the advantage of an independent atmosphere' 

 circulating at pleasure, and of any desired quality of heat and moisture be- 

 comes of incalculable value. Admitting damp to be the greatest enemy that 

 tender plants have to encounter during winter ; that a current of air dispels that 

 damp as effectually, and much more safely, than fire heat (the least excess of 

 which is always hurtful, often fatal), the conclusion is, that plants in a damp 

 state are really more benefited by the application of fire heat from the com- 

 motion it creates in the air, than from any trifling addition it may make to 

 the temperature. Hence the great utility of Mr. Penn's apparatus, with which 

 the same quantity of fuel will create a tenfold current, giving at all times the 

 power of maintaining sufficient heat to keep plants in a state of health without 

 the possibility of injuring them. Some persons suppose that plants will thrive 

 better in a lower circulating medium, than they will do in a higher stagnated 

 one ; (that is, that they will do as well in a current of air heated to 60° as 

 they would where it is stagnated and heated to 70° ;) then I reply that we 

 know that plants of a more hardy nature will bear much more heat with the 

 air in a state of circulation, than they will when it is stagnant. Therefore 

 with an atmosphere so truly under our control as that produced by Mr. 

 Penn, we may reasonably expect an approximation in the habits of plants, that 

 will render the division of structures, however desirable under any circum- 

 stances, less a matter of absolute necessity than it has hitherto been. It is 

 I think, not improbable that this may be the case to an extent that will render 

 green-house grapes equal to the present forced fruit. 



But it must appear premature, even to guess at the ciFects to be produced 

 by a system the influence of which must be universal. Still we can hardly 

 expect too much from any thing so strictly in accordance with the grand ope- 

 rations of nature. Mr, Penn's method is not, however, entirely dependent 

 upon the ventilation. Supposing that to go for nothing, still there is much 

 to recommend it left. His boiler gives unlimited command of heat at the 

 least possible expense of fuel, and the whole apparatus is constructed with 

 truly self-acting simplicity, which is an object of the last importance; and his 

 manner of heating so many houses from one fire possesses advantages that 

 must be obvious to all conversant with such matters, and must alone render 

 it superior to all others. The saving of labour, consequently of expense, is 

 great; while there is a certainty that one fire, upon which everything depends, 

 will be better attended to, and therefore perform the work better than if it 

 were left to half a score fireplaces. Altogether, I have no hesitation in say- 

 ing that, where the houses of an establishment are not too far apart to be 

 connected, they will be better attended to than if they were separate. I do 

 not mean to say that heat is often denied when absolutely necessary, but a 

 little would often do good, when we are loth to heat a separate apparatus to 

 produce it. Where the whole are connected, this can be done without, I mav 

 say, either time or trouble, and often, as chance may be, without a farthing of 



